WASHINGTON — The Security and Exchange Commission on Thursday proposed rules designed to stem conflicts of interest and provide more transparency for credit-rating companies. They also proposed banning “flash orders,” which give some traders a split-second edge in trading stocks.

A study on social media use released earlier this month found that people who spent excessive time on Facebook also made riskier decisions -- performing as poorly in a famous psychological test as people dependent on substances such as cocaine or heroin.

Amazon is planning to use its massive cloud computing service to jump into the streaming market for video game play, according to a new report from the Information. The service, which could potentially bring top-notch titles to virtually anyone with a smartphone or streaming device, could make Amazon a major competitor in the space already in play by Microsoft and...